Process for making anodes of solid manganese peroxid.



I No Drawing. Application filed November 3,

srATEs PATENT oEEIcE.

MAX HUTI-I, F QERLiN-GHARLOTTENBURG, GERMANY, AssIeNoR r0 SIEMENS &

HALISKE'QA. a, or BERLIN, GERMANY, A CORPORATION or GERMANY.

: PROCESS FOR.v MAKIbIG ANODES 0F SOLID MANGANESE PER-0X11).

new and useful Improvements in Processes for Making Anodes of Solid Manganese Peroxid, of which the following 1s a spec1- fication.

My invention relates to anodes which are made from solid peroxid of manganese and consists in brief in an improvement of the process described in my U; S. Patent No.

, 93 5109, dated September 28, 1909, in which either pure nitrate of manganese or'c'rystalline peroxid of manganese is brought into forms with the. addition of nltrate of manganese and thereupon heated in order to change the nitrate of manganese into peroxidof manganese. When using plates of normal strength, the conductivity of anodes which are made according to the above mentioned patent, will not be sufficient for high currents, andit is the object of my present invention to obtain an increase of the conductivity of the anodes, which is relatively dependent upon the strength of the material, by subsequently treating the anode by a precipitation of peroxid of manganese.

I According to my present invention, the process of making an0des,'therefore, is carried out in such a manner, that at the first decomposition of the .material, which alS brought into the form, the pure nitrate of manganese or crystalline peroxid of manganese w'th an admixture of nitrate of manse will form a main layer of peroxid of manganese. The material added will then again be decomposed into peroxid of manganese, which however will not deposit as an additional layer upon said former layer, but which-seems to enter into the pores of the same, thereby increasing the density thereof. The main layer of peroxid of manganese Wlll therefore be so to sayimpregnated bythe subsequent decomposition without, however, causing the thickness of the anodefto increase in proportion to the quantity of material which is introduced. a 4

This impregnating process now may ,either be carried out according to 'the aforementioned patent in two manners which are different from each other. In the first place -the peroxid of manganese which is formed.

I Specificationof Letters Patent. Patented Mar. 4, 1919.

1914, Serial No. 870,083. Renewed July 24, 1918. Serial No. 246,610. l 1

by the decomposition of nitrate of manganese may be made to cool off in the form and thereupon new material may be added which is again decomposed by being heated.

Also during the decomposition of the material which is first brought into theform the proper quantities of nitrate of manga-,

nese may be continuously added and thus the process of manufacture may-be rendered uninterrupted. The number and duration of the several working phases, as. well as the quantity of the material to be added is dependent upon'the quality of the desired ture, the anodes will also obtain a greater mechanical strength and a greater life-time.

Since however According to my invention instead of thel crystalline peroxid of manganese also natural manganese dioxid may be employed as original material. For this purpose natural manganesedioxid is made to small pieces and rendered free from impurities by treatmentwith sulfuric acid or another acid which does not decomposeperoxid of manganese.

The powder of manganese dioxid which is thus gained is thereupon well washed out, dried and wetted with a solution of nitrate of manganese and thereupon pressed into the desired form. The remaining steps of the process for making electrodes according to my present invention are in accordance with those described in the aforementioned U. S. patent. 7

By the pressing process the material will become of such a strength, that it will enof the same may now be repeated a number of times until the electrode possesses the suflicient density and conductivity. In order anod together with the connectingpiece for "the'terminal will consist of one integral piece which is entirely made by 'the pressing process. a

Anodes made according to the aforedescribed process are free from injurious im-' purities and possess a good conductivity for the current; the same as those which are ymade by presslng the artificlal peroxld 01' with nitrate of manmanganese together ganese-J l 5 Having. .thus described my invention-I claim as new and desiretoec'u're by Letters Patent of thelUnited State s f 1. A process for enhardeningand increasing the densityand conduc-tivity of anodes made from peroxidof manganese or from a compound of manganese convertiblet'by'heatj into peroxid of manganese which consists in subsequently treating the anode by 'a--precipitationof peroxi'd of manganese.

-2. A process for 'enhardening-l ind iiicreasing the density and COIIdHCCIVltY O-f anodes made from peroxid of. manganese or from a compound of manganese conlventible by heat into peroxid of, manganese, which consists in forming the' main body of the] anode bya first layer ;of-peroxid of man;

'ganese and repeatedly treating such layer with nitrate of manganese "while applying heat thereto. i a 3. A process for enhardenlng and increasing the density and condwctivity of anodes made from peroxid of manga se or from a compound of manganese, convertible by heat into peroxid of manganese, which consists in forming the main body of theanodeby'a first layer of peroxid of manganese and repeatedly heating and treating such layer with nitrate of manganese.

, 4. -A process for enhardening and increasing, the'densi ty and conductivity of anodes made from peroxid of manganese or from a compound of manganese convertible by heat into peroxid of manganese, which consists in. repeatedly treating such material, with nitrate (if-manganese and in applying heat thereto,- said nitrate of manganese being continuously introduced during heating.

5. A process for enhardening and increasing the density and conductivity of anodes "made from natural peroxid of manganese, which consists in repeatedly heating and-cooling the same and continuously introdulcing [nitrate of manganese during heating; e a i I 6. A process for enhardening and increasing the density and conductivity of anodes lmadegfrom p'eroxid of manganese or from compound of manganese convertible by heat'into peroxid of manganese, which cm- I Sists informing the mainbody of the anode by a first layer of peroxid of manganese, repeate'dlytreating such layer with ni'trateof 1 manganese andin applying heat thereto, said nitrate of manganese being repeatedly inmade from natural peroxid of manganese,

material in succession and introducing nitrateiof manganese after coollng.

In testimony whereof I aflix my signature in presence of two witnesses.

' WOLDE A HaUP'r,

' z'HnNRYHASPER.

- MAX HUTH.

which consists in heating and cooling'the 

